The present invention generally relates to circuit modules having electric circuits in a form of a module.
Conventionally, electric circuits are provided on a circuit board, and a computer board manufactured by Micromint is an example of such a circuit board. This computer board has a group of terminals provided along only one side of the computer board. For this reason, there is a problem in that the size of the computer board is approximately 330 mm.times.120 mm which is relatively large.
Another example of such a circuit board has extended memories of a computer on a circuit board. This extended memory board has a group of terminals provided along only one side of the extended memory board, and the size thereof is large.
FIGS. 1 and 2 show an example of a conventional a computer board 10 manufactured by Micromint. In FIGS. 1 and 2, the computer board 10 has mounted thereon a central processing unit (CPU) 11, a first POACH (PC On A Chip, trademark) 12 manufactured by Zymos, a second POACH 13, third POACHs 14 and 15, a basic input output system read only memories (BIOS-ROMs) 16 and 17, a memory 18 made up of eighteen 256 kbit dynamic random access memories (DRAMs) 19, a bipolar programmable read only memory (PROM) 20, a delay line 21, an integrated circuit group 22 for producing access timings, for example, a calendar circuit part 23, and a keyboard controller 24. All of these elements of the computer board 10 are mounted on only a top surface of a board 25. A terminal group 26 is provided along one side of the board 25.
The POACHs 12 through 15 are integrated circuits (ICs). For example, the POACHs 12 and 13 are peripheral controller chips, the POACH 14 is an address buffer chip, and the POACH 15 is a data buffer chip.
The computer board 10 is assembled into a computer (not shown) by plugging in the terminal group 26 to a connector (not shown) and inserting the computer board 10 in an upright position.
FIGS. 3 and 4 show the first POACH 12. The first POACH 12 has a stage 100, a plurality of leads 101, a semiconductor chip 102, a plurality of wires bonded to connect chip 102 and the leads 101, and a synthetic resin-formed package portion 104. Each lead 101 has a shape such that the inner end thereof is narrow and the outer end thereof is wide. A length L.sub.2 of each lead 101 is about 8 mm which is approximately four times a length L.sub.1 of the wire 103 which is about 2 mm. For this reason, the size of the first POACH 12 is 29 mm.times.29 mm which is relatively large. A thickness t.sub.1 of the first POACH 12 is 3.9 mm.